Drawing sheet glass



April s, 1924;

J. WHITTEMORE DRAWING SHEET GLAS S Filed April zo. 1921 FuE-.1

INV ENTER Jngmor ATTJRNEY 1 I l// I To all whom t mi; concern.'

Patented Apr. 8, 1924.

UNITED t STATES PATENT FFECE.

SHEET GLASS COMPANY, 0F TOLEDO,

OHIO, A OOBPOBATIOH 0F OHIO.

DRAWING SHEET GLASS.

Application led April 20, 1821. Serial No. 462,88-

Be it known that I, JAMES Wm'rnmonn, a citizen of the United States, residin at Detroit,.in the county of Wayne and Sgtate of Michigan, have invented new and useful `Improvements in Drawing Sheet Glass, of whlch the following is a' specification.A

When a sheet of glass is drawn from a mass of molten giass, for some reason there are produced ve shallow inequalities or waves on the sur ace,l which are very undesirable. If these waves could be climi nated, a sheet could be drawn which would beqluite similar, if not equal, to plate glass in c earness of vision.

vItis my opinion that these waves are' largely produced byv variations in the sur face tensionV at different points in the sheet width, and that these waves are due to the slightly different heat conditions in the glass at the base of the meniscus.

In order to more nearly equalize the heat throughout: l.theswidth of thesheet and thus overcome some or all of these waves, I heat the glass along the lines of the base of the. meniscus and thus equalize the surface tension' at all oints. w This adding of the heat to the surface may, in some cases, require that the middle or mass of glass which goes into the sheet,

shall be slightly lowered in temperature,

ing bar and, in such cases I emlploy a .coo

e meniscus.

beneath the middle of t In the use of the surface heater and the core cooler for the sheet in addition toequalizing the surface tension at all points; t

the temperature of the sheet throughout is "more nearl the internal strains are eliminated; and further, the mass being of more nearly uniform tem erature, in cooling a )flatter and more er ect sheet will be produced.

edrawingsv Figure Lis a transverse vertical section throughfthe drawing pot of one forni of myfaparatus, the view being taken suby on line 1--1 of Fig. part of the sheet being broken away to disclose the heater.

Figure 2 is a Vertical central1 section throughFig. l; and

Figure 3 is a similar section o f a modification.

fsheet, so, as far as uniform and a large part of In the drawings I have shown my invention in connection with an apparatus of the well known Colburn type new in use. r The shallow draw pot or receptacle 1 is continually supplied with molten glass from a suitable source such as a continuous tank furnace. The sheet of glass 4 is drawn up from the glass in the pot by suitable drawing means, not shown,' 5 is the so'called meniscus at the point where the sheet is drawn from the mass. v

At each side of the sheet and at the base of the meniscus where the surface tension is greatest, I apply heat. As shown in Figs. 1 and 2, this may be an electric heater 6, enclosed in an insulating covering i', with an opening for the moreeifective discharge of the heat at the bottom as indicated at 8, this slot being at the base of the mexscus.

Instead of an electric heater, I may employ any other means of heating, such as a slotted gas pipe burner 9, shown in Fig. 3 and in such case I prefer to have the Hannes jetted downward against the travel of the Y ssible, to localize the heat at the base of t ie meniscus.

These heaters may be raised and lowered to and from the surface to regulate the degree of heat added: But all that is required 1s to slightly ,soften the surface of the glass so as to e ualize the temperature of the surface atft e base of the meniscus, for the purpose of equalizing the surface tension all along the width of the sheet.

flu 'the example shown in Figs. l and 2 of the drawin the heaters 7 are supported adjustably rom the coolers 12, by means of stems 13,l longitudinall adjustable through supporting rod let, which in turn is adjust ably carried by ears 15 projecting from the sheet-side of the coolers.

In cases where it is desirable to cool the o y supporting bars 11,

equalize he surface tension and eliminate i mass while the exterior is raised in temperature by the heaters, with the advantageous results heretofore pointed out.

at I claim as my invention is:

1. In a sheet glass drawing apparatus, a receptacle containing molten glass from whicha sheet of glass is drawn, means within the molten glass in the receptacle for cooling the glass drawn into the interior o the sheet, and heaters adjacent the sheet soi ree for heating the glass drawn into the suirface portions of the/ sheet.

2li The process of drawing sheet glass from a molten mass of glass, consisting in cooling from within the molten mass the glass which is being drawn into the interior of the sheet, and simultaneously heating the surface portions of the mass at the sheet source.

3. In a sheet lass drawing apparatus,

ya receptacle containing molten glass, means a receptacle containing molten lass,'means'.

for drawing a sheet of coolin bar submerged within the molten glass eneath the line of the draw of the sheet, and heaters extending across each face of the sheet, near the molten mass.

6. In a sheet glass drawing apparatus, a receptacle containing molten glass, means for drawing a sheet therefrom, a, cooling bar submerged in the glass beneath the meniscus, and across each face of of the meniscus.

Signed at Santa Barbara, in the county of Santa Barbara and State of California, this 8th day of March, 1921.

JAMES VVHITTEMORE.

the sheet near the base glass t erefrom, a`

electric heaters extending 

